(boilz) The principle that the volume of a given mass of an ideal gas is inversely proportional to its pressure, as long as temperature remains constant. Boyle's law is a subcase of the ideal gas law. Compare Charles's law.

a relation concerning the compression and expansion of a gas at constant temperature. This empirical relation, formulated by the physicist Robert Boyle in 1662, states that the pressure (p) of a given quantity of gas varies inversely as its volume (v) at constant temperature; i.e., in equation form, pv = k, a constant. The relationship was also discovered by the French physicist Edme Mariotte (1676).